To restore their snow-white appearance, you can use popular folk recipes or use special preparations.
Read more about how to remove yellowness from plastic in the article.
Acetone
Not the safest way for you and your plastic.
Before using acetone, test how it reacts with this type of plastic on a small area. If the reaction does not take place and the plastic does not dissolve, then you can safely apply acetone to a cotton pad and wipe the yellowed areas. This method is more suitable for dense and non-bending plastic.
Part I. Malicious butadiene
The plastic most often used in the production of old computers was ABS, which is known for its tendency to yellow over just a few years.
Most plastics, including ABS, degrade when exposed to heat and light in the presence of oxygen. This effect is called thermal oxidation and photo-oxidation, respectively. Therefore, it is recommended to store plastic products in a cool, dark place. But this is not a salvation, and later I will explain why. ABS plastic is made up of three main components: acrylonitrile, butadiene and styrene (see Figure 1). We are interested in butadiene and styrene, since acrylonitrile does not actively participate in yellowing or the Retr0bright process.
Rice.
1. Basic structure of ABS. The hexagon is a benzene molecule. Source: [1] In the presence of heat or high-energy light, oxygen molecules attack ABS plastic.
This process is shown in Fig. 2 below. Fig.2 Oxidation of the butadiene molecule.
The wavy lines indicate the rest of the chain. From carbon atoms located next to double bonds, hydrogen is separated more easily, so oxygen penetrates here [8].
As a result, an unstable chemical compound, hydroperoxide, is formed (also shown in Fig. 2). One of the oxygen atoms in the hydroperoxide molecule decides that it is too crowded here and pushes out the neighboring oxygen and hydrogen atoms (Fig. 3). Fig.3
The freed -OH group is called a radical. At the moment, he is not tied to anything and is in free flight - a free radical. Further, to find shelter, it acts as a parasite in the styrene group [5,7]. This long, malicious process of introduction into a poor styrene molecule occurs in several stages, which are shown in Fig. 4.
Fig. 4
After the introduction of the radical, the styrene group is cleaved, forming a nondescript yellow compound called 2-hydroxymuconic acid or simply muconic acid. The yellow color is formed due to the so-called conjugation bonds. A conjugated system is any material with an alternating set of single and double bonds (Fig. 5).
Rice.
5. Pairing example. Conjugated bonds are highlighted in red. Source: [3] In Fig. 4 we see that in muconic acid many double bonds alternate with single ones. Without conjugation, the chemical component does not absorb visible light well enough and appears white to us because all colors are reflected. If conjugation is present, then the chemical component absorbs several colors of the visible spectrum. In the case we are considering, muconic acid absorbs blue and violet light, reflecting the yellow and red spectrum, which presents this nondescript shade of yellow to our eyes. But that's not all!
Hydrogen peroxide
If the plastic is not very yellowed, then just wipe it with hydrogen peroxide. This can be done with a cotton pad or sponge. Peroxide does an excellent job of removing soot, grease, smoke, and most other household contaminants.
To increase the effectiveness of the product, you can make a special solution. Mix hydrogen peroxide (1/2 cup) and any stain remover (1 tablespoon is enough) with water, then rinse the surface.
What is the cause of yellowing?
The loss of plastic's original whiteness may be due to several factors. This is due to improper care of the material and exposure to the environment.
The main causes of yellowing:
Temperature changes. Sudden changes in temperature over time lead to the appearance of microcracks on the surface and destruction of the top layer with the dye included in it.- Burnout. Direct exposure to sunlight is the most common cause of yellowness.
- Wrong choice of cleaning products. First of all, this applies to compositions that are aggressive in their impact.
- Settlement of soot and other pollutants. This problem is typical for products located in the kitchen, in industrial premises or in places with poor ecology.
- Low quality material. Violation of technology in the production of plastic can only manifest itself over time. One of these manifestations is yellowing.
If the surface of the plastic does not have serious integrity violations, it is quite possible to lighten it.
Dish detergent
One of the gentle ways to get rid of yellowed plastic is to clean it with a soapy solution. This type of cleaning copes well with light yellowing, which occurs due to soot or grease deposits.
To prepare the solution, you will need dishwashing detergent and dissolved laundry soap. Mix soap and detergent and add water, then use a soft brush to scrub the surface.
Why does plastic turn yellow?
There can be many reasons why plastic objects turn yellow.
- Oxidation. Plastic is a synthetic polymer that oxidizes when exposed to oxygen. This happens slowly but inevitably.
- Ultraviolet radiation. Windows most often suffer from this, so light stabilizers are added to high-quality structures during manufacturing.
- Temperature changes. They negatively affect the properties of the material, and it loses its former whiteness.
- Exploitation. In a room where people smoke or cook without an exhaust hood, nicotine deposits, soot and grease appear on surrounding objects, which give an untidy appearance.
- Incorrect care. Overzealous cleaning with abrasives and hard brushes leaves damage. Dirt gets into them, and the shade of the product changes.
- Poor quality raw materials. Recycling waste is a noble cause, but in order for plastic to have a white color, it is necessary to use certain additives, and some manufacturers neglect this.
If you come across a copy made of low-quality material, then, alas, nothing can be done. But in all other cases, you can try to restore its former appearance.
Stain removers and bleaches
Yellowness and other stains from plastic can be removed using bleach and a chlorine stain remover. Such products should be used very carefully, and be sure to wear a mask and gloves. People prone to allergies should not use this method.
The solution is made like this: dissolve one tablespoon of bleach or stain remover in one liter of water. You need to soak for 11-12 hours, then rinse the plastic parts and wipe dry.
Recipe Retr0bright
WARNING!!!
Please note that hydrogen peroxide is a corrosive agent and, if handled carelessly, can cause serious chemical burns to the skin, as well as blinding if it gets into the eyes. If you decide to do this experiment, it is highly recommended to use glasses and gloves.
Merlin's original recipe
To prepare the magic mixture “Retr0bright” you will need:
- 500 ml of hydrogen peroxide with a concentration of 10 to 15%;
- 2 heaped tablespoons xanthan gum (available in health food stores and online);
- 1 teaspoon glycerin (sold at the pharmacy);
- 1/4 teaspoon Oxy laundry booster.
Add the hydrogen peroxide and gum to the blender and blend on high speed for 5 seconds. Add glycerin and stir for another 5 seconds. Let the mixture sit for about a minute, then stir again for 5 seconds. The result should be a thick gel that can be placed in a dark container (such as a coffee can covered with dark film) for storage. Just DO NOT add Oxy until you are ready to use this gel.
To use the mixture, mix the final component into it and apply it to the part, then place the part in sunlight for several hours. This procedure can be repeated.
Here is the experimental result of whitening a Commodore 64. The process was carried out in several stages and took a total of 8 hours:
Translator's note:
The original recipe is described here, for which there are two alternative options given on the main site. The authors separately warn that the responsibility for using your own ingredients and introducing technological improvements to the process falls entirely on you.
PS from the editors of RUVDS
This article came to us in an unusual way, and one might even say that it found us on its own.
When translating a series of two articles (Restoring and Upgrading the BBC Micro and Upgrading the BBC Master) dedicated to the restoration of retro electronics, we contacted the author and asked him some questions, including from user comments. In response to one of these comments, the author kindly sent us a pdf file with the original article that you read today. And since many are interested not so much in the chemical background of all these processes, but in the recipe for the miracle cure itself, it was decided to refine and supplement the material. List of sources
[1] ABS suppliers. (2021). Acrylonitrile Butadiene Styrene; Chemical Retrieval on the Web. polymerdatabase.com/Polymer%20Brands/ASB.html [2] Adeniyi, J. B. (1984). Clarification and discussion of chemical transformations involved in thermal and photo-oxidative degradation of ABS. European Polymer Journal, 20(3), 291–299. doi.org/10.1016/0014-3057(84)90050-8 [3] Ashenhurst, J. (2016, September 8). Conjugation and color(+ how bleach works). Master Organic Chemistry. www.masterorganicchemistry.com/2016/09/08/conjugation_and_color [4] Khalil, I., Quintens, G., Junkers, T., & Dusselier, M. (2020). Muconic acid isomers as platform chemicals and monomers in the biobased economy. Green Chemistry, 22(5), 1517–1541. doi.org/10.1039/C9GC04161C [5] Kulich, D. M., & Gaggar, S. K. (1996). Weathering of acrylonitrile-butadiene-styrene plastics: Compositional effects on impact and color. In Polymer Durability (Vol. 249, pp. 483–501). American Chemical Society. doi.org/10.1021/ba-1996-0249.ch031 [6] Pickett, J. E. (2004). Reversible post-exposure yellowing of weathered polymers. Polymer Degradation and Stability, 85(1), 681–687. doi.org/10.1016/j.polymdegradstab.2004.03.008 [7] Searle, N. D., Maecker, N. L., & Crewdson, L. F. E. (1989). Wavelength sensitivity of acrylonitrile–butadiene–styrene. Journal of Polymer Science Part A: Polymer Chemistry, 27(4), 1341–1357. doi.org/10.1002/pola.1989.080270418 [8] Tiganis, B. E., Burn, L. S., Davis, P., & Hill, A. J. (2002). Thermal degradation of acrylonitrile–butadiene–styrene (Abs) blends. Polymer Degradation and Stability, 76(3), 425–434. doi.org/10.1016/S0141-3910(02)00045-9 [9] Tiganis, B., Davis, P., Burn, L., & Gotama, J. (2002). The Mechanism Of Photo-Oxidative Degradation Of Acrylonitrile-Butadiene-Styrene (Abs) Resins Used In Pipes. www.irbnet.de/daten/iconda/CIB9222.pdf [10] Wyzgoski, M. G. (1976). Effects of oven aging on ABS, poly(Acrylonitrile-butadiene-styrene). Polymer Engineering & Science, 16(4), 265–269. doi.org/10.1002/pen.760160408
Alcohols
Plastic usually does not react to alcohols and alcohol solutions, so they can be safely used for bleaching. To do this, put on rubber gloves, pour a little alcohol onto a cotton pad, and walk over the yellowed surface.
After treatment, it is not necessary to wash off the alcohol, but it is recommended to ventilate the room.
Recommendations
The following tips from cleaning experts will help you cope better with the task:
- Before you begin bleaching, the surface must be prepared - remove dust and dirt.
- All work should be carried out wearing rubber gloves to protect your hands.
- It is necessary to consider what kind of plastic will be processed. For some types of products, special products are produced marked “for refrigerators”, “for microwaves”, etc.
- After cleaning is completed, the plastic surface should be wiped dry.
- When treating plastic against yellowing with vinegar essence, alcohol, Dimexide and other substances, you must remember that if the cleaning agent gets on areas with inscriptions, they can also be erased.
- To clean small plastic items, it is convenient to use an old toothbrush.
The most complete and useful information about methods and means of removing yellow spots and yellowness from various surfaces and products is presented in this section.
Perhydrol
This product can be found in almost any pharmacy. Use perhydrol carefully and ensure that it does not heat up. Soak a sponge in perhydrol and wipe the plastic surface 3-4 times. Be sure to rinse the plastic with water afterwards!
For the best effect, mix perhydrol with stain remover and a liter of water.
Benefits of laundry soap
This product has a pungent odor and a good cleansing effect. To do this, just use a small amount of soap, a soft sponge and warm water.
The alkaline composition of this product ensures the rapid destruction of fatty deposits and deep dirt and forms a protective film on the surface.
- To do this, it is enough to use 300 g of laundry soap and 5 liters of warm liquid.
- What composition can be used to clean kitchen furniture, window sills and plastic dishes.
- After soap treatment, it is recommended to wipe all surfaces with a damp cloth.
Dye
It happens that there is nothing you can do to help plastic. Initially, the quality was poor, or the yellow spots looked more like brown. The only way for such cases is spray paint. Perhaps this is the easiest and fastest option for getting rid of stains on plastic.
There are many ways to return plastic to its original color, and there is an option for each case. All the methods presented above are available, and you can easily use them at home, the main thing is not to forget about personal protection. Now your plastic is white again, and if it turns yellow again, you know what to do.
Remember, you should wear gloves and a mask when working with chemicals. Take care of your health.
Part III. Nintendo history?
The question has been raised in the retro computer community about whether flame retardants, particularly BFRs (brominated flame retardants), cause yellowing.
There is a possibility that this assumption originated at Nintendo, but I was unable to confirm this. The short answer is, “Yes, BFRs cause yellowing.” Brominated flame retardants can be cleaved to form conjugated chains with double bonds that are involved in the yellowing process. However, the amount of BFR relative to the total volume of plastic is small and the effect is therefore very small.
Rice.
7. Example of brominated flame retardant and its structure But BFRs can cause yellowing through another mechanism. Similar to butadiene, BFRs are also attacked by oxygen to produce free radicals, which then attack the styrene chains, causing the breakdown of styrene. This confirms that BFRs contribute to yellowing, but not in the way many assume.
How to restore whiteness to household appliances
You can bleach plastic on a refrigerator that has turned yellow from time or improper care using effective means:
- Unicum. The domestic product removes stains well without leaving streaks. It can be used to treat external and internal surfaces.
- Lighthouse. Another Russian remedy. It is universal and can be used to wash any plastic product.
To restore the whiteness of household items and electronics, you can use the German Nord LAN spray or the domestic product Magic Power Techno.
Caring for plastic products
Household appliances and white window frames, when properly cared for, retain a beautiful color and aesthetic appearance. Simple tips will help:
- Wash the plastic regularly with soapy water, use soft sponges, and microfiber cloths to remove excess moisture;
- completely eliminate abrasive products; they remove dirt, but at the same time scratch the surface; with regular use, it becomes covered with scratches in which dirt accumulates;
- do not smoke indoors;
- place fabric or knitted napkins under flower pots;
- after washing with soapy water, treat the surface with polish, the film that forms protects against microdamage;
- remove random stains immediately with any approved preparation;
- protect from direct sunlight.
General information
Also, one of the most important qualities is safety, so they can be safely used in residential areas. The materials used for the manufacture of plastic panels undergo all necessary tests and have a quality certificate. Another important advantage is that plastic panels are moisture resistant and also resistant to various chemicals. Another plus is the huge range of colors of plastic panels.
Important: when choosing plastic panels, you need to know exactly where they will be mounted, because what is suitable for the kitchen is not suitable for the hallway. For example, matte panels are difficult to clean from greasy stains, so they are not suitable for a kitchen backsplash.
